Tricyclic lactam and sultam derivatives and their use as histone deacetylase inhibitors

ABSTRACT

A compound of formula (I) 
                         
wherein A and B are optionally substituted cyclohexenyl or phenyl groups, X is carbonyl or sulfonyl, and Y is 5–7 atoms-linker, is useful as histone deacetylase inhibitors, particularly for inhibiting cell proliferation.

The invention relates to tricyclic lactam and sultam derivatives, or pharmaceutically-acceptable salts thereof, which possess anti-cell-proliferation activity such as anti-cancer activity and are accordingly useful in methods of treatment of the human or animal body. The invention also relates to processes for the manufacture of said tricyclic lactam and sultam derivatives, to pharmaceutical compositions containing them and to their use in the manufacture of medicaments of use in the production of an anti-cell-proliferation effect in a warm-blooded animal such as man.

BACKGROUND OF THE INVENTION

Transcriptional regulation is a major event in cell differentiation, proliferation, and apoptosis. Transcriptional activation of a set of genes determines cell destination and for this reason transcription is tightly regulated by a variety of factors. One of its regulatory mechanisms involved in the process is an alteration in the tertiary structure of DNA, which affects transcription by modulating an accessibility of transcription factors to their target DNA segments. Nucleosomal integrity is regulated by the acetylation status of the core histones. In a hypoacetylated state, nucleosomes are tightly compacted and thus are nonpermissive for transcription. On the other hand, nucleosomes are relaxed by acetylation of the core histones, with the result being permissiveness to transcription. The acetylation status of the histones is governed by the balance of the activities of histone acetyl transferase (HAT) and histone deacetylase (HDAC). Recently; HDAC inhibitors have been found to arrest growth and apoptosis in several types of cancel cells, including colon cancer, T-cell lymphoma, and erythroleukemic cells. Given that apoptosis is a crucial factor for cancer progression, HDAC inhibitors are promising reagents for cancer therapy as effective inducers of apoptosis (Koyama, Y., et al., Blood 96 (2000) 1490–1495).

Several structural classes of HDAC inhibitors have been identified and are reviewed in Marks, P. M., et al., Journal of the National Cancer Institute 92 (2000) 1210–1216. More specifically, a tricyclic imid, i.e. “scriptaid” is described by Su, G. H., et al., Cancer Res. 60 (2000) 3137–3142.

It was now found that certain tricyclic lactam and sultam derivatives possess anti-cell-proliferation properties which are more potent than those in the aforementioned references. These properties are due to HDAC inhibition.

DESCRIPTION OF THE INVENTION

According to the invention there are provided tricyclic lactam and sultam derivatives of the formula I

denotes a cyclohexenyl group or a phenyl group,

denotes a cyclohexenyl or a phenyl group which may be unsubstituted or substituted by one or more substituents independently selected from a halogen atom, a nitro group, an amino group, an (1–4C)alkylamino group, a di[(1–4C)alkyl]-amino group, or an (1–4C)alkanoylamino group,

X is a carbonyl group or a sulfonyl group,

Y is a straight chain alkylene group comprising 5, 6, or 7 carbon atoms, wherein one CH₂ group may be replaced by an oxygen or a sulfur atom, or wherein 2 carbon atoms form a C═C double bond, and which is either unsubstituted or substituted by one or two substituents selected from (1–4C)alkyl and halogen atoms,

their enantiomers, diastereoisomers, racemates and mixtures thereof and pharmaceutically acceptable salts.

A suitable value for a substituent when it is a halogen atom is, for example, fluoro or chloro; when it is (1–4C)alkyl is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl; when it is (1–4C)alkylamino is, for example, methylamino, ethylamino or propylamino; when it is di-[(1–4C)alkyl]amino is, for example, dimethylamino, N-ethyl-N-methylamino, diethylamino, N-methyl-N-propylamino or dipropylamino; when it is (1–4C)alkanoylamino is, for example, formylamido, acetamido, propionamido or butyramido.

Examples for physiologically acceptable salts of compounds of formula I are salts with physiologically acceptable bases. These salts can be, among others, alkali, ammonium and alkylammonium salts, for example sodium, potassium, calcium, or tetramethylammonium salts.

Particular preferred compounds of the invention include, for example, tricyclic lactam and sultam derivatives of the formula I

denotes a cyclohexenyl group or a phenyl group,

denotes a cyclohexenyl or a phenyl group which may be unsubstituted or substituted by a substituent independently selected from a chloro or bromo atom, a nitro group, an amino group, an (1–4C)alkylamino group, a di[(1–4C)alkyl]-amino group, or an (1–4C)alkanoylamino group,

X is a carbonyl group or a sulfonyl group, and

Y is a straight chain alkylene group comprising 5, 6, or 7 carbon atoms, wherein one CH₂ group may be replaced by an oxygen or a sulfur atom, or wherein 2 carbon atoms form a C═C double bond, and which is either unsubstituted or substituted by one or two substituents selected from (1–4C)alkyl and halogen atoms,

their enantiomers, diastereoisomers, racemates and mixtures thereof and pharmaceutically acceptable salts.

Preparation of the Compounds of the Invention

A tricyclic lactam and sultam derivative of the formula I, or a pharmaceutically-acceptable salt thereof, may be prepared by any process known to be applicable to the preparation of chemically-related compounds. Such processes, when used to prepare a tricyclic lactam and sultam derivative of the formula I, or a pharmaceutically-acceptable salt thereof, are provided as a further feature of the invention and are illustrated by the following representative examples in which, unless otherwise stated, A, B, X, and Y have any of the meanings defined hereinbefore. Necessary starting materials may be obtained by standard procedures of organic chemistry. The preparation of such starting materials is described within the accompanying non-limiting examples. Alternatively, starting materials are obtainable by analogous procedures to those illustrated which are within the ordinary skill of an organic chemist.

(a) One preferred method for the preparation of compounds of the formula I is the deprotection of compounds of the formula II

wherein A, B, X and Y have the meaning defined, hereinbefore, and Z is a suitable protecting group. Compounds of the formula II are new and included in the present invention.

Suitable protecting groups are the benzyl, p-methoxybenzyl, tert.butyloxycarbonyl, trityl, or silyl groups such as the trimethylsilyl or dimethyl-tert.butylsilyl group. The reactions carried out depend on the type of the protecting group. When the protecting group is a benzyl or p-methoxybenzyl group, the reaction carried out is a hydrogenolysis in an inert solvent such as an alcohol like methanol or ethanol, in the presence of a noble metal catalyst such as palladium on a suitable carrier such as carbon, barium sulfate, or barium carbonate, at ambient temperature and pressure. When the protecting group is the tert.butyloxycarbonyl, trityl, or a silyl group such as the trimethylsilyl or dimethyl-tert.butylsilyl group, the reaction is carried out in the presence of acids at a temperature between −20° C. and 60° C., preferably between 0° C. and ambient temperature. The acid may be a solution of hydrochloric acid in an inert solvent such as diethyl ether or dioxane, or trifluoroacetic acid in dichloromethane. When the protecting group is a silyl group such as the trimethylsilyl or dimethyl-tert.butylsilyl group, the reaction is carried out in the presence of a fluoride source such as sodium fluoride or tetrabutyl ammoniumfluoride in an inert solvent such as dichloromethane.

Compounds of the formula II are obtained by the reaction of a lactam or sultam of the formula III

wherein A, B, and X have the meaning defined hereinbefore, with a compound of formula IV W—Y—CONHO-Z  (IV) wherein W is a displaceable group and Y and Z have the meaning defined hereinbefore, in the absence or presence of a suitable base.

A suitable displaceable group W is, for example, a halogeno, or sulphonyloxy group, for example a chloro, bromo, methanesulfonyloxy or toluene-p-sulfonyloxy group. A suitable base is, for example, an organic amine base such as, for example, pyridine, 2,6-lutidine, collidine, 4-dimethylaminopyridine, triethylamine, morpholine, N-methylmorpholine or diazabicyclo[5.4.0]undec-7-ene, or, for example, an alkali or alkaline earth metal carbonate or hydroxide, for example sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide or potassium hydroxide.

The reaction is conveniently carried out in the presence of a suitable inert solvent or diluent, for example an alkanol or ester such as methanol, ethanol, isopropanol or ethyl acetate, a halogenated solvent such as methylene chloride, chloroform or carbon tetrachloride, an ether such as tetrahydrofuran or 1,4-dioxane, an aromatic solvent such as toluene, or a dipolar aprotic solvent such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidin-2-one or dimethylsulfoxide. The reaction is conveniently carried out at a temperature in the range, for example, 10 to 250° C., preferably in the range 40–200° C.

Compounds of the formula III are commercially available or can be prepared according to Dannerth, F., J. Am. Chem. Soc. 29 (1908) 1319 (cylisation of 1-amino-naphthalene-8-sulfonic acids to yield 1,8-naphthosultams), Goldstein, F., Helv. Chim. Acta 15 (1932) 1366 (halogenation of 1H-benzo[cd]indol-2-one), Varney, M. D., et al., J. Med. Chem. 35 (1992) 663–676 (nitration of 1H-benzo[cd]indol-2-one).

(b) Another preferred method for the preparation of compounds of the formula I involves the reaction of compounds of the formula V

wherein A, B, X, and Y have the meaning defined hereinbefore, with hydroxylamine. This reaction typically involves a two-step one-pot procedure. In the first step, the carboxylate of the formula V becomes activated. This reaction is carried out in an inert solvent or diluent, for example, in dichloromethane, dioxane, or tetrahydrofuran, in the presence of an activating agent. A suitable reactive derivative of an acid is, for example, an acyl halide, for example an acyl chloride formed by the reaction of the acid and an inorganic acid chloride, for example thionyl chloride; a mixed anhydride, for example an anhydride formed by the reaction of the acid and a chloroformate such as isobutyl chloroformate; an active ester, for example an ester formed by the reaction of the acid and a phenol such as pentafluorophenol, an ester such as pentafluorophenyl trifluoroacetate or an alcohol such as methanol, ethanol, isopropanol, butanol or N-hydroxybenzotriazole; an acyl azide, for example an azide formed by the reaction of the acid and an azide such as diphenylphosphoryl azide; an acyl cyanide, for example a cyanide formed by the reaction of an acid and a cyanide such as diethylphosphoryl cyanide; or the product of the reaction of the acid and a carbodiimide such as dicyclohexylcarbodiimide. The reaction is carried out between −30° C. and 60° C., conveniently at or below 0° C. In the second step, hydroxylamine is added to the solution at the temperature used for the activation, and the temperature is slowly adjusted to ambient temperature.

Compounds of the formula V are prepared from compounds of the formula VI

wherein A, B, X and Y have the meaning defined hereinbefore and R is an alkyl group, for example, a methyl, ethyl, or tert. butyl group or benzyl group, by hydrolysis. The conditions under which the hydrolysis is carried out depend on the nature of the group R. When R is a methyl or ethyl group, the reaction is carried out in the presence of a base, for example, lithium hydroxide, sodium hydroxide, or potassium hydroxide in an inert solvent or diluent, for example, in methanol or ethanol. When R is the tert.butyl group, the reaction is carried out in the presence of an acid, for example, a solution of hydrochloric acid in an inert solvent such as diethyl ether or dioxane, or trifluoroacetic acid in dichloromethane. When R is the benzyl group, the reaction is carried out by hydrogenolysis in the presence of a noble metal catalyst such as Palladium on a suitable carrier, such as carbon.

Compounds of the formula VI are prepared from compounds of the formula III

wherein A, B, and X have the meaning defined hereinbefore, by reaction of compounds of the formula VII W—Y—COO—R  (VII) wherein W, Y and R have the meaning defined hereinbefore, in the absence or presence of a suitable base.

A suitable base is, for example, an organic amine base such as, for example, pyridine, 2,6-lutidine, collidine, 4-dimethylaminopyridine, triethylamine, morpholine, N-methylmorpholine or diazabicyclo[5.4.0]undec-7-ene, or, for example, an alkali or alkaline earth metal carbonate or hydroxide, for example sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide or potassium hydroxide.

The reaction is conveniently carried out in the presence of a suitable inert solvent or diluent, for example an alkanol or ester such as methanol, ethanol, isopropanol or ethyl acetate, a halogenated solvent such as methylene chloride, chloroform or carbon tetrachloride, an ether such as tetrahydrofurane or 1,4-dioxane, an aromatic solvent such as toluene, or a dipolar aprotic solvent such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidin-2-one or dimethylsulfoxide. The reaction is conveniently carried out at a temperature in the range, for example, 10 to 250° C., preferably in the range 40–200° C.

(c) A third preferred method for the production of compounds of the formula I involves the reaction of compounds of the formula VIII

wherein A, B, X, and Y have the meaning defined hereinbefore and R′ is an (1–4C)alkyl group, for example, a methyl or ethyl group, with hydroxylamine in the presence of a suitable base.

The reaction is carried out in an inert solvent or diluent such as methanol or ethanol at temperatures between 0° C. and 100° C., conveniently at or near ambient temperature, and at a pH between 9 and 11. A suitable base is, for example, an alcoholate, for example, sodium methylate.

(d) Those compounds of the formula I wherein one of the substituents is an amino group are prepared by the reduction of a derivative of the formula I wherein the substituent is a nitro group. The reduction may conveniently be carried out by any of the many procedures known for such a transformation. The reduction may be carried out, for example, by the hydrogenation of a solution of the nitro compound in an inert solvent or diluent as defined hereinbefore in the presence of a suitable metal catalyst such as palladium or platinum. A further suitable reducing agent is, for example, an activated metal such as activated iron (produced by washing iron powder with a dilute solution of an acid such as hydrochloric acid). Thus, for example, the reduction may be carried out by heating a mixture of the nitro compound and the activated metal in a suitable solvent or diluent such as a mixture of water and an alcohol, for example, methanol or ethanol, to a temperature in the range, for example, 50 to 150° C., conveniently at or near 70° C.

(e) Those compounds of the formula I wherein one of the substituents is an (1–4C)alkanoylamino group, are prepared by acylation of a derivative of the formula I wherein the substituent is an amino group. A suitable acylating agent is, for example, any agent known in the art for the acylation of amino to acylamino, for example an acyl halide, for example an alkanoyl chloride or bromide, conveniently in the presence of a suitable base, as defined hereinbefore, an alkanoic acid anhydride or mixed anhydride, for example acetic anhydride or the mixed anhydride formed by the reaction of an alkanoic acid and an alkoxycarbonyl halide, for example art alkoxycarbonyl chloride, in the presence of a suitable base as defined hereinbefore. In general the acylation is carried out in a suitable inert solvent or diluent as defined hereinbefore and at a temperature, in the range, for example, −30 to 120° C., conveniently at or near ambient temperature.

According to a further aspect of the invention there is provided a pharmaceutical composition which comprises a tricyclic lactam or sultam derivative of the formula I, or a pharmaceutically-acceptable salt thereof, as defined hereinbefore in association with a pharmaceutically-acceptable diluent or carrier. The composition may be in a form suitable for oral administration, for example as a tablet or capsule, for parenteral injection (including intravenous, subcutaneous, intramuscular, intravascular or infusion) as a sterile solution, suspension or emulsion, for topical administration as an ointment or cream or for rectal administration as a suppository. In general the above compositions maybe prepared in a manner using conventional excipients. The tricyclic lactam or sultam derivative will normally be administered to a warm-blooded animal at a unit dose within the range 5–5000 mg per square meter body area of the animal, i.e. approximately 0.1–100 mg/kg, and this normally provides a therapeutically-effective dose. A unit dose form such as a tablet or capsule will usually contain, for example 1–250 mg of active ingredient. Preferably a daily dose in the range of 1–50 mg/kg is employed. However the daily dose will necessarily be varied depending upon the host treated, the particular route of administration, and the severity of the illness being treated. Accordingly the optimum dosage may be determined by the practitioner who is treating any particular patient.

According to a further aspect of the present invention there is provided a tricyclic lactam or sultam derivative of the formula I as defined hereinbefore for use in a method of treatment of the human or animal body by therapy. It was surprisingly found that the compounds of the present invention possess anti-cell-proliferation properties which arise from their histone deacetylase inhibitory activity. Accordingly, the compounds of the present invention provide a method for treating the proliferation of malignant cells. Accordingly, the compounds of the present invention are useful in the treatment of cancer by providing an anti-proliferative effect, particularly in the treatment of cancers of the breast, lung, colon, rectum, stomach, prostate, bladder, pancreas and ovary. In addition, the compounds according to the present invention will possess activity against a range of leukemias, lymphoid malignancies and solid tumors such as carcinomas and sarcomas in tissues such as the liver, kidney, prostate and pancreas.

Thus, according to this aspect of the invention there is provided the use of a tricyclic lactam or sultam derivative of the formula I, or a pharmaceutically-acceptable salt thereof, as defined hereinbefore in the manufacture of a medicament for use in the production of an anti-cell-proliferation effect in a warm-blooded animal such as man.

According to a further feature of this aspect of the invention there is provided a method for producing an anti-cell-proliferation effect in a warm blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a lactam or sultam derivative as defined hereinbefore.

The anti-cell-proliferation treatment defined hereinbefore may be applied as a sole therapy or may involve, in addition to the compounds of the invention, one or, more other anti-tumor substances, for example those selected from, for example, mitotic inhibitors, for example vinblastine; alkylating agents, for example cis-platin, carboplatin and cyclophosphamide; inhibitors of microtubule assembly, like paclitaxel or other taxanes; antimetabolites, for example 5-fluorouracil, capecitabine, cytosine arabinoside and hydroxyurea, or, for example, intercalating antibiotics, for example adriamycin and bleomycin; immunostimulants, for example trastuzumab; DNA synthesis inhibitors, e.g. gemcitabine; enzymes, for example asparaginase; topoisomerase inhibitors, for example etoposide; biological response modifiers, for example interferon; and anti-hormones, for example antioestrogens such as tamoxifen or, for example antiandrogens such as (4′-cyano-3-(4-fluorophenylsulfonyl)-2-hydroxy-2-methyl-3′-(trifluoromethyl)propionanilide, or other therapeutic agents and principles as described in, for example, DeVita, Vincent, T., Jr., Hellmann, S., Rosenberg, S. A., In: Cancer: Principles & Practice of Oncology,; 5^(th) Ed., Lippincott-Raven Publishers, 1997. Such conjoint treatment may be achieved by way of the simultaneous, sequential or separate dosing of individual components of the treatment. According to this aspect of the invention there is provided a pharmaceutical product comprising a lactam or sultam derivative of the formula I as defined hereinbefore and an additional anti-tumor substance as defined hereinbefore for the conjoint treatment of cancer.

The invention will now be illustrated in the following non-limiting examples in which, unless otherwise stated:

-   -   (i) evaporations were carried out by rotary evaporation in vacuo         and work-up procedures were carried out after removal of         residual solids such as drying agents by filtration;     -   (ii) operations were carried out at ambient temperature, that is         in the range 18–25° C. and under an atmosphere of an inert gas         such as argon or nitrogen;     -   (iii) column chromatography (by the flash procedure) and high         pressure liquid chromatography (HPLC) were performed on Merck         Kieselgel silica or Merck Lichroprep RP-18 reversed-phase silica         obtained from E. Merck, Darmstadt, Germany;     -   (iv) yields are given for illustration only and are not         necessarily the maximum attainable;     -   (v) melting points were determined using a Mettler SP62         automatic melting point apparatus, an oil-bath apparatus or a         Kofler hot plate apparatus.     -   (vi) the structures of the end-products of the formula I were         confirmed by nuclear (generally proton) magnetic resonance (NMR)         and mass spectral techniques (Micromass Platform II machine         using APCI or Micromass Platform ZMD using electrospray);     -   (vii) intermediates were not generally fully characterized and         purity was assessed by thin layer chromatography (TLC);     -   (viii) the following abbreviations have been used: DMF,         N,N-dimethylformamide.

EXAMPLE 1

8-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-octanoic acid hydroxyamide

(a) In an ice bath, 14 ml triethylamine was added to a suspension of 3.2 g (20 mmol) O-benzylhydroxylamine hydrochloride in 150 ml dichloromethane. Stirring was continued until the solution became clear. Then, 4.5 g (20 mmol) 8-bromo octanoic acid was added, followed by 5.6 g (22 mmol) bis-(2-oxo-3-oxazolidinyl)-phosphorylchloride. Stirring was continued at ambient temperature for 18 h. The solution was extracted twice with 150 ml each of 1M aqueous hydrochloric acid and twice with 150 ml each of 1M aqueous sodium bicarbonate. The organic solvent was removed i. vac. to give 5.1 g (78%) of 8-bromo-octanoic acid benzyloxyamide as a colorless oil. MS: 330 (M+H⁺)

(b) A solution of 1,8-naphthalenesultam (0.3 g, 1.5 mmol), 8-bromo-octanoic acid benzyloxy-amide (0.48 g, 1.5 mmol), and 0.2 g (1.4 mmol) potassium carbonate in DMF (7 ml) was heated to 120° C. for 2 h. After cooling to ambient temperature, water was added and extracted with ethyl acetate. The organic phase was washed with water, dried over sodium sulfate, filtered, and the solvent was evaporated. The residue was purified by column chromatography using ethyl acetate:heptane=8:2 as eluent. There was thus obtained 0.35 g (80%) 8-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-octanoic acid benzyloxyamide as an amorphous solid. MS:453 (M+H⁺).

(c) 8-(1,1-Dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-octanoic acid benzyloxyamide (0.47 g) in methanol (30 ml) was hydrogenated for 1.5 h in the presence of palladium on barium sulfate at ambient temperature and pressure. The catalyst was removed by filtration and the solvent was evaporated. The residue was purified by column chromatography (silica gel; ethyl acetate as eluent). There was thus obtained 8-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-octanoic acid hydroxyamide (61%) as a colorless oil. MS: 363 (M+H⁺).

EXAMPLE 2

7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

(a) Bis(2-oxo-3-oxazolidinyl)phosphoryl chloride (1.9 g, 7.5 mmol) is added to a solution of 7-bromohepatanoic acid (1.3 g, 6.2 mmol) and triethylamine (3.5 ml, 48 mmol) in methylene chloride (35 ml). After 15 min, benzylhydroxylamine hydrochloride (1 g, 6.3 mmol) is added and stirring is continued for 16 h. The organic phase is extracted with 1N aqueous hydrochloric acid and saturated aqueous sodium chloride solution, then dried over sodium sulfate and filtered. The solvent is removed i.vac. and the residue is purified by column chromatography (sicica gel; ethyl acetate:heptane=1:1) to give 7-bromoheptanoic acid benzyloxyamide (97%) as a colorless oil. MS (M+H⁺)=316.

(b) In a manner analogous to that of example 1(b), 7-bromo-heptanoic acid benzyloxyamide 0.46 g, 1.5 mmol) was reacted with 1,8-naphthalenesultam (0.3 g, 1.5 mmol) in the presence of potassium carbonate (0.2 g, 1.4 mmol) to give 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid benzyloxyamide as an amorphous solid (yield 0.4 g, 62%; purified by column chromatography using silica gel and ethyl acetate:heptane=1:1 as an eluent). MS (M+H⁺)=439.

(c) In a manner anologous to that of example 1(c), 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid benzyloxyamide was hydrogenated to give the title compound in 98% yield as an amorphous solid. (M−H⁺)=347.

EXAMPLE 3

8-(2-oxo-2H-benzo[cd]indol-1-yl)-octanoic acid hydroxyamide

(a) In a manner analogous to that of example 1(b), 8-bromo-octanoic acid benzyloxyamide 0.49 g, 1.5 mmol) was reacted with benzo[cd]indol-2(1H)-one (0.25 g, 1.5 mmol) in the presence of potassium carbonate (0.2 g, 1.4 mmol) to give 8-(2-oxo-2H-benzo[cd]indol-1-yl)-octanoic acid benzyloxyamide as an amorphous solid (yield 0.12 g, 19%; purified by column chromatography using silica gel and ethyl acetate:heptane=1:1 as an eluent). MS (M+H⁺)=417.

(b) In a manner analogous to that of example 1(c), 8-(2-oxo-2H-benzo[cd]indol-1-yl)-octanoic acid benzyloxyamide was hydrogenated to give the title compound in 98% yield as an amorphous solid. (M−H⁺)=325.

EXAMPLE 4

7-(2-Oxo-6,7,8,8a-tetrahydro-2H-benzo[cd]indol-1-yl)-heptanoic acid hydroxyamide

(a) In a manner analogous to that of example 2(b), 7-bromo-heptanoic acid benzyloxy-amide 0.46 g, 1.5 mmol) was reacted with benzo[cd]indol-2(1H)-one (0.25 g, 1.5 mmol) in the presence of potassium carbonate (0.2 g, 1.4 mmol) to give 7-(2-oxo-2H-benzo[cd]indol-1-yl)-heptanoic acid benzyloxyamide as an amorphous solid (yield 0.08 g, 13%; purified by column chromatography using silica gel and ethyl acetate:heptane=1:1 as an eluent). MS (M+H⁺)=403.

(b) In a manner anologous to that of example 1(b), 7-(2-oxo-2H-benzo[cd]indol-1-yl)-heptanoic acid benzyloxyamide was hydrogenated. Slight overhydrogenation gave the title compound in 98% yield as an amorphous solid. (M+H⁺)=317.

EXAMPLE 5

In an analogous manner to that described in the examples 1–4 the following compounds are prepared:

(a) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-hexanoic acid hydroxyamide

(b) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-5-methyl-heptanoic acid hydroxyamide

(c) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-4-methyl-heptanoic acid hydroxyamide

(d) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl-3-methyl-heptanoic acid hydroxyamide

(e) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-heptanoic acid hydroxyamide

(f) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-chloro-heptanoic acid hydroxyamide

(g) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2,2-dimethyl-heptanoic acid hydroxyamide

(h) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2,2-dichloro-heptanoic acid hydroxyamide

(i) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-octanoic acid hydroxyamide

(j) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-hexanoic acid hydroxyamide

(k) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-4-oxa-heptanoic acid hydroxyamide

(l) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-methyl-4-oxa-heptanoic acid hydroxyamide

(m) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-heptanoic acid hydroxyamide

(n) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-5cis-heptenoic acid hydroxyamide

(o) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-5trans-heptanoic acid hydroxyamide

(p) 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-3-oxa-heptanoic acid hydroxyamide

(q) 7-(5-Bromo-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

(r) 7-(5-Nitro-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

(s) 7-(5-Amino-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

(t) 7-(5-Methyl-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

(u) 7-(5-Acetylamino-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide

EXAMPLE 6 Evaluation of HDAC Inhibitory Properties of the Compounds of the Invention

To determine the HDAC inhibitory properties of the compounds of the invention an assay was performed using an aminocoumarin derivative of an omega-acetylated lysine as substrate for the enzyme. This assay has been described in detail in the literature (Nucleic Acid Research 1999, 27, 2057–2058. Using the protocol described therein, the inhibitory effect of representative compounds was determined at a concentration of 10 nM. The observed inhibition rates for selected compounds are shown in Table 1:

TABLE 1 Title compound of example No. Inhibitory effect at 10 nM in % 1 64 2 90 3 82

LIST OF REFERENCES

-   Dannerth, F., J. Am. Chem. Soc. 29 (1908) 1319 -   DeVita, Vincent, T., Jr., Hellmann, S., Rosenberg, S. A., In:     Cancer: Principles & Practice of Oncology,; 5^(th) Ed.,     Lippincott-Raven Publishers, 1997 -   Goldstein, F., Helv. Chim. Acta 15 (1932) 1366 -   Koyama, Y., et al., Blood 96 (2000) 1490–1495 -   Marks, P. M., et al., Journal of the National Cancer Institute     92 (2000) 1210–1216 -   Su, G. H., et al., Cancer Res. 60 (2000) 3137–3142 

1. A compound of formula I

denotes a cyclohexenyl group or a phenyl group,

denotes a cyclohexenyl or a phenyl group which is unsubstituted or substituted by one or more substituents independently selected from a halogen atom, a nitro group, an amino group, an (1–4C)alkylamino group, a di[(1–4C)alkyl]-amino group or an (1–4C)alkanoylamino group, X is a carbonyl group or a sulfonyl group, Y is a straight chain alkylene group comprising 5, 6, or 7 carbon atoms, wherein each CH₂ group is unsubstituted or substituted by an oxygen or sulfur atom, or 2 carbon atoms form a C═C double bond, and which is either unsubstituted or substituted by one or two substituents selected from (1–4C)alkyl and halogen atoms, their enantiomers, diastereoisomers, racemates and mixtures thereof, or a pharmaceutically accetable salt thereof.
 2. The compound of formula I according to claim 1 selected from the group consisting of 8-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-octanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide; 8-(2-oxo-2H-benzo[cd]indol-1-yl)-octanoic acid hydroxyamide; 7-(2-oxo-6,7,8,8a-tetrahydro-2H-benzo[cd]indol-1-yl)-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-hexanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-5-methyl-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-4-methyl-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-methyl-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-heptanoic acid hydroxyamide; and 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-chloro-heptanoic acid hydroxyamide.
 3. A process for the manufacturing of a compound of formula I according to claim 1 which comprises reacting a compound of formula III

wherein A, B, and X have the meaning defined above with a compound of formula IV, W—Y—CONHO—Z  (IV) wherein W is a displaceable group, Z is a protecting group and Y has the meaning defined above, in the presence of a suitable base, whereafter the protecting group Z is split off.
 4. A process for the manufacturing of a compound of formula I according to claim 1 which comprises reacting a compound of formula VI

wherein A, B, X and Y have the meaning defined above, and R is hydrogen or a alkyl group, with hydroxylamine in the presence of a base.
 5. The compound of formula I according to claim 1 selected from the group consisting of 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2,2-dimethyl-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2,2-dichloro-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-octanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-hexanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-4-oxa-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-methyl-4-oxa-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-5cis-heptanoic acid hydroxyamide; 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-3-oxa-5trans-heptanoic acid hydroxyamide; and 7-(1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-2-methyl-oxa-heptanoic acid hydroxyamide.
 6. The compound of formula I according to claim 1 selected from the group consisting of 7-(5-bromo-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide; 7-(5-nitro-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide; 7-(5-amino-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide; 7-(5-methyl-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide; and 7-(5-acetylamino-1,1-dioxo-2H-naphtho[1,8-cd]isothiazol-2-yl)-heptanoic acid hydroxyamide.
 7. The process of claim 3 further comprises converting the compound to its enantiomers, diastereoisomers, racemates or pharmaceutically acceptable salt thereof.
 8. A pharmaceutical composition containing as active ingredient a compound of formula I according to claim 1 in admixture with a pharmaceutically acceptable excipient or diluent. 